Device for transporting and reading flat material

ABSTRACT

A device for reading flat material having an endless perforated belt, guided over two rollers, one of which is driven. Material is brought from a feeder to an inlet arranged on both sides of the rollers and the belt transports the material to an outlet. The material is retained against the belt by vacuum. The device is adjustable relative to the feeder and, in one position, the entrance to the inlet is at the level of the feeder and, in the other position, the entrance to the inlet is at the level of the feeder. At least one reading device is provided, for reading the markings from the material being transported on the belt. On adjustment from the one position to the other, a reversal in the direction of rotation of the driven roller occurs and the reading device faces that side of the belt, the entrance to the inlet of which is at the level of the feeder.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns a device for reading sheet material.

2. Prior Art

Such a device is known from U.S. Pat. No. 3,980,294. It consists of anendless, perforated belt guided over two rollers. Between the upper andlower section of the belt there is a low-pressure chamber. Above theupper section of the belt there is a light source. This light source hasa slit. A paper to be copied is held against this belt by low pressureacting at the perforations of the belt, and in this way the paper iscarried past the light source, where the markings of the sheet aredetected through the slit. With this known device, markings can bedetected that are located on the top side of the sheet. In contrast,markings on the bottom side of the sheet cannot be detected.

A device for electronic transmission of information in text form onpaper sheets or reels of paper is known from DE 198 07 944 A1, whereinthe paper is transported between transport rollers and opposing counterrollers driven to rotate. In order to detect information on both sidesof the paper in a passage, there is a device for detecting informationon each side of the paper, where the information is converted intoelectronic signals in a control unit and then transmitted to a receiver.

SUMMARY OF THE INVENTION

The problem dealt with by the invention is the design of a deviceaccording to this class so that markings on both the top side of thematerial and also on the bottom side can be detected.

This problem is solved with the features of the invention by theprovision of a device for reading sheet material, consisting of anendless, perforated belt guided over two rollers, of which one isdriven, where material is guided from a feeding device to an inlet andthe belt transports the material to an outlet, wherein the material isheld against the belt by a low pressure acting at the perforations ofthe belt and there is at least one reading device that detects markingsof the material transported by the belt, characterized in that there isan inlet on both sides of one of the rollers, in that the device can beadjusted relative to the feeding device, and in one position, one inletis located at the height of the feeding device, and in the otherposition, the other inlet is located at the height of the feedingdevice, in that for a change from one position to the other, thedirection of rotation of the driven rollers is reversed, and in that theone or more reading devices are directed towards the correspondingsection of the belt, whose inlet is located at the height of the feedingdevice.

The device may be further characterized in that each section of the beltis covered by a transparent plate or characterized in that the platescan be removed. Further, the device may be characterized in that thereis a low-pressure chamber between the first and the other section orcharacterized in that between the first and the other section there isat least one fan, whose direction of rotation is reversible, and in thatthe suction side of the fan is directed towards the correspondingsection, whose inlet is located at the height of the feeding device.

The device may be characterized in that the transparent plates arereduced at the inlets or characterized in that the feeding deviceconsists of two transport rollers arranged at a distance from each otherwith corresponding counter rollers. Further, the driven roller is drivenby an electric motor that can change its direction of rotation. Also,the driven roller can be driven by a toothed belt that engages one sideof the roller in one position and engages the other side of the rollerin the other position. In addition, the reading device can be adjustedin the direction of a section and perpendicular to this direction.

The device may be characterized in that in the region of an outlet thereis a detector that detects the leading edges of the material and thatgenerates a signal reducing the speed of the belt when the leading edgeis detected. In the device, the periphery of the rollers has pins thatengage the perforations of the belt.

The invention relates to a device for the reading of flat material,comprising an endless perforated belt, guided over two rollers, of whichone is driven. The material is brought from a feeder device to an inletand the belt transports said material to an outlet, whereby the materialis retained against the belt by a vacuum acting on the perforations ofthe belt and at least one reading device is provided, for reading themarkings from the material being transported on the belt. Inconventional devices of this type only markings may be read which lie onthe upper surface of the sheet. The aim of the invention is to providean embodiment of the device with which markings may also be read whichlie on the under surface of the sheet. Said aim is achieved, whereby aninlet is arranged on both sides of the rollers, said device isadjustable relative to the feed unit and, in the one position, the oneinlet, is at the level of the feed unit and, in the other position, theother inlet is at the level of the feed unit. On an adjustment from theone position to the other a reversal in the direction of rotation of thedriven roller occurs and the at least one reading device faces that sideof the belt, the inlet of which is at the level of the feed unit.

In addition to the advantage of two-sided readability, another advantageis that there is no restriction on the reading area. Reading is possibleboth while moving and at a standstill. Due to the small masses to bemoved, high acceleration is possible for the sheet material to betransported.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment is explained in more detail in the following withreference to the drawings. Shown are:

FIG. 1: a side view of the device for reading markings on the top sideof a sheet;

FIG. 2: a side view corresponding to FIG. 1 for reading markings on thebottom side of a sheet;

FIG. 3: a vertical section through a first embodiment of the device, and

FIG. 4: a vertical section through a second embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The device features an endless, perforated belt 1 that is guided overtwo rollers 2, 3, of which one roller is driven. The top section 4 ofthe belt 1 is covered by a transparent plate 5 that is preferably madeof glass. There is another transparent plate 7 underneath the lowersection 6. The plates 5, 7 are located a slight distance from the belt1.

According to FIG. 3, two fans 9 are located between the upper and lowersections 4, 6. The direction of rotation of the fans 9 can be reversed.Instead of the fans 9, the space between the sections 4, 6 can beconfigured as a low pressure chamber 8, as shown in FIG. 4. This isconnected to the suction side of a compressor 18.

There are two corresponding transport rollers 10, 11 before the rollers2, 3 at a horizontal distance from each other, and a counter roller 12contacts each transport roller. The rollers 2, 3 and the plates 5, 7 canbe adjusted in height relative to the transport rollers 10, 11 and theircounter rollers 12.

The periphery of the rollers 2, 3 has pins 19 that engage theperforations 20 of the belt 1.

If the top side of the sheet is to be read, then it is guided over theright transport rollers 10, 11 to the upper inlet 13. Here, the fans 9are switched so that a low pressure is created above the fans 9. In thisway, a low pressure is created through the perforations of the belt 1 atthe upper section 4, and this low pressure holds the sheet to betransported by the belt 1 against the upper section 4. During transportalong the section 4, the upper side of the sheet is scanned by a readingdevice 15 that is arranged above the plate 5.

If the speed of the sheet is to be reduced during reading, or if thesheet is to be brought to a standstill, then there can be a detectorthat is arranged above the plate 5 and that detects the leading edge ofthe sheet before it reaches the outlet. The transport speed of the sheetcan be changed by means of the signal generated in this way.

If the bottom side of the sheet is to be read, then the rollers 2, 3with the belt 1 and the plates 5, 7 are moved upwards into the positionshown in FIG. 2, where the transport rollers 10, 1 1 with their counterrollers 12 are located at the height of the lower inlet 14. The readingdevice 15 is arranged underneath the plate 7 in this case. With thetransformation into the upper position, the direction of rotation of therollers 2, 3 is simultaneously reversed. The same applies for the fans9, where a low pressure is generated at the lower section 6.

The sheet guided from the transport rollers 10, 11 to the lower inlet 14is fixed to the lower section 6 due to the low pressure and istransported past the reading device 15 now located below. FIGS. 3 and 4also shows the detector 16, which is used for the detection of theleading edge of the sheet.

As already indicated, the fans 9 can be eliminated if the space betweenthe upper and the lower sections 4, 6 is configured as a low-pressurechamber 8.

In order to simplify retrofitting, there can be two reading devices 15,one above the plate 5 and one below the plate 7.

The plates 5, 7 can be removable. The direction of rotation of therollers 2, 3 can be reversed by an electric motor M3, which can reverseits direction of rotation. In the embodiment shown in FIGS. 1 and 2, theroller 2 is driven by a toothed belt 17, which engages to the left or tothe right with teeth of the roller 2 according to the height anddirection of rotation of this roller.

The transport rollers 10, 11 with their counter rollers 12 at the inletsand outlets are driven by a common electric motor M1 at the same rpmsynchronously with the belt speed.

What is claimed is:
 1. Device for reading sheet material, consisting of an endless, perforated belt guided over two rollers, of which one is driven, where material is guided from a feeding device to an inlet and the belt transports the material to an outlet, wherein the material is held against the belt by a low pressure acting at the perforations of the belt and there is at least one reading device that detects markings of the material transported by the belt, characterized in that there is an inlet on both sides of one of the rollers, in that the device can be adjusted relative to the feeding device, and in one position, one inlet is located at the height of the feeding device, and in the other position, the other inlet is located at the height of the feeding device, in that for a change from one position to the other, the direction of rotation of the driven rollers is reversed, and in that the one or more reading devices are directed towards the corresponding section of the belt, whose inlet is located at the height of the feeding device.
 2. Device according to claim 1, characterized in that each section of the belt is covered by a transparent plate.
 3. Device according to claim 2, characterized in that the plates can be removed.
 4. Device according to claim 2, characterized in that the transparent plates are reduced at the inlets.
 5. Device according to claim 1, characterized in that there is a low-pressure chamber between the first and the other section.
 6. Device according to claim 1, characterized in that between the first and the other section there is at least one fan, whose direction of rotation is reversible, and in that the suction side of the fan is directed towards the corresponding section, whose inlet is located at the height of the feeding device.
 7. Device according to claim 1, characterized in that the feeding device consists of two transport rollers arranged at a distance from each other with corresponding counter rollers.
 8. Device according to claim 1, characterized in that the driven roller is driven by an electric motor that can change its direction of rotation.
 9. Device according to claim 1, characterized in that the driven roller is driven by a toothed belt that engages one side of the roller in one position and engages the other side of the roller in the other position.
 10. Device according to claim 1, characterized in that the reading device can be adjusted in the direction of a section and perpendicular to this direction.
 11. Device according to claim 1, characterized in that in the region of an outlet there is a detector that detects the leading edges of the material and that generates a signal reducing the speed of the belt when the leading edge is detected.
 12. Device according to claim 1, characterized in that the periphery of the rollers has pins that engage the perforations of the belt. 